When waiting for my mother to try on a dress in a department store in Kyoto…
Salesgirl, to me: 旅行ですか? (Are you on a trip?)
Me: はい、そうです。 (Ah, yes.)
Salesgirl: えぇ！わかりますか？！(Eh! You understand [Japanese]?!)
If she thought I didn’t understand Japanese, why speak to me in Japanese in the first place? lol.